Would it be possible to have at least three options for border/overscan?
Original- Every pixel output by the core is visible untouched. Yes you would see garbage along with a colored border (depending on the game), etc. (this is completely missing right now)
Black - Border/overscan area is colored black. (this seems to be the current setting when overscan area is displayed)
Off - Border/overscan area is disabled/not displayed at all.
EDIT: Rysha has expressed that she may add this at a later time.